Koltanowski George. Colle System

Coraopolis: Chess Enterprises, 1990. — 90 p. — ISBN: 0-931462-983.One of the most solid openings in chess, White can play the Colle(1.d4 d5 2.Nf3 Nf6 3.e3 e6 4.Bd3) and give himself a simple, solid setup with clear strategic purposes.The flexibility allow White to go for different kinds of attacks. He can play the Koltanowsky 5.c3 and aim to bolster the center, or play the Zukertort 5.b3 and fianchetto the bishop on the long diagonal with pieces aimed at the Black Kingside.